- Analog Station Set and Central Office Line Protector - Protects up to 8-wires (4-pairs) using 110 punchdown block on the input and 110 punchdown block or 4 RJ11 or 2 RJ45 on output. - Auto-Resetting Technology: PTC resistors open when a surge occurs protecting your equipment but unlike other fuses the PTCs close again once the surge passes. - Expandable modular system - Applications: Analog and Central Office lines for PBX or KSU - Agency Approval: UL 497A (Secondary) - Grounding Requirements: Uses Electrical AC Ground - Recommended Grounding Impedance: